Commutator smoothing device



April 1963 w. H. RHINDRESS 3,083,600

COMMUTATOR SMOOTHING DEVICE Filed July 20, 1961 2 Sheets-Sheet 1 if m E If! [H i F G. 2 INVENTOR.

WALTER H. RHINDRESS ATTORNEYS April 1963 w. H. RHINDRESS 3,083,600

COMMUTATOR smoo'mmc DEVICE Filed July 20, 1961 2 Sheets-Sheet 2 Jdh 7M ATTORNEYS United States Patent Claims. (ill. 82-4) The present invention relates to devices for smoothing commutators, and has specific reference to a hand operated portable smoothing device of novel design.

The present invention is a continuation-in-part of copending application Serial No. 508,969, filed May 17, 1955, md entitled commutator Smoothing Device, now abandoned.

The principal object of the invention is to provide an improved commutator smoothing device which has a feed spindle and a collet for releasably gripping the armature shaft, and which may be removably mounted on a support base or secured within a vise, as desired.

Another object of the invention is to provide a commutator smoothing device with a novel collet control for ensuring a firm lock on the armature shaft.

Still another object is to provide a commutator smoothing device in which the means for mounting the armature shaft is rotated and simultaneously fed longitudinally with respect to a fixed smoothing tool,

A further object is to provide a commutator smoothing device with a concealed thread feed which is not exposed to dust and dirt no matter what the position of the feed, and which further has an improved bearing arrmgement so as to eliminate chatter during the feed of the armature shaft.

An additional object of the invention is to provide a snap lock control for locking and for releasing the spindle feed.

With the above and other objects and advantageous features which will become apparent as the description proceeds, the invention consists of a novel arrangement of parts more fully disclosed in the detailed description thereof, in conjunction with the accompanying drawings, and more specifically defined in the claims appended thereto.

In the drawings:

FIG. 1 is a side elevation of a preferred construction embodying the invention, parts being broken away;

FIG. la is a fragmentary top plan view of FIG. 1;

FIG. 2 is an end view of FIG. 1 with parts being shown broken away;

FIG. 3 is a side view of feed nut of HG. 1, parts being broken away;

FIG. 4 is a partial sectional View taken along lines 44 in PEG. 1;

FIG. 5 is an enlarged sectional view of a portion of the hollow shaft showing an extreme position thereof in the hollow frame that encloses the shaft threaded portion;

FIG. 6 is a sectional View taken along line 5-5 in FIG. 1;

FIG. 7 is an exploded perspective view of the snaplock parts;

FIG. 8 is a perspective View of a collet diameter adjustment spacer; and FIG. 9 is a side elevational view of the collet that is locked in the hollow shaft.

it has been found desirable to provide a construction for a portable armature smoothing device, which may be readily mounted on a work table or in a vise, as desired, and which includes a stationary frame with a rotatable hollow shaft, the hollow shaft having feed threads for meshing with a releasable feed guide that is mounted on the frame and that is adapted to be snapped into and out of feeding engagement with the shaft threads. The hollow shaft is further provided with means for looking it 3,083,660 Patented Apr. 2, 1963 against rotation, whereby a collet mounted therein and adapted to releasably receive an armature shaft may be drawn into the hollow shaft by a handle control which is threaded to the collet end, until the armature shaft is securely locked in the collet and the collet and the handle tightly frictionally engage the hollow shaft for simultaneous rotation of the hollow shaft, the collet and the armature shaft.

To this end, a collet of standard type having a split conical head portion and a threaded rear end is employed, and the collet is mounted in a hollow shaft having a conical beveled mouth, whereby a draw'in threaded fitting seated in the other end of the hollow shaft is adapted to be turned by a handle to pull the collet inwardly for gripping an armature shaft. The hollow shaft is locked against rotation during this grip-ping pull, and the feed guide is located in released position. When the armature shaft is tightly locked in place, the hollow shaft is tightly gripped between the collet head and the draw-in fitting, and entire unit is then shifted to unlocked position. The feed guide is then snap set into feeding engagement with the threaded portion of the hollow shaft, and the handle is rotated to simultaneously rotate and feed the hollow shaft, the collet and the armature forwardly, wherein the armature commutator is engaged by a smoothing tool that is mounted in the stationary frame.

Referring to the drawings, the commutator smoothing device embodied herein is generally indicated at 10 and includes a hollow frame 11 that is formed with a cylindrical bore 12 (H6. 4) and has a depending extension 13 of narrow width joined thereto that is adapted to be readily locked in a vise or detachably received within an upper slot recess 14 of a base 15. The base 15 is adapted to be bolted to the top of a table or the like and is provided with a lock screw 16, as shown in FIG. 2, for locking the extension 13 within the slot recess 14.

Rotatably and slidably mounted in the bore 12 of the frame 11 is a hollow shaft 17 which as shown in FIGS, 4 and 5 has a central threaded portion that is adapted to be engaged by a feed guide generfily indicated at 19. As illustrated more clearly in FIG. 5, the entire length of the threaded portion 18 is enclosed by both ends of the frame 11 and remains enclosed even through the hollow shaft may have been moved to the outer limit position shown in H6. 5 during the connnutator smoothing operation. The threaded portion 18 is thus protected from dust and grime and will always be clean for positive engagement with the feed guide 19.

As shown more clearly in FIG. 4, the hollow shaft 17 is firmly supported in position by the frame 11, the opposed inner surfaces of the frame that flank the threaded portion 18 defining spaced bearing surfaces for the hollow shaft. it is seen that these spaced bearing surfaces support substantially the major length of the hollow shaft and prevent chattering of the shaft during the commutator smoothing operation. It is of extreme importance that there always be bearing engagement at opposite ends of the threaded portion 155, no matter in what relative position the hollow shaft and frame may be, since without this bearing at both ends of the threaded portion, it has been found that severe chattering takes place when the commutator is being smoothed. Thus, the structure which insures that the threaded portion is always enclosed and protected against dirt and grime also simultaneously and inherently provides the proper bearing for smooth and effective feed of the commutator.

Referring to FIG. 7, the feed guide 19 is shown in cluding a cylindrical portion 20 that is adapted to project through an opening 21 (PEG. 6) formed in the frame ll. The cylindrical portion 26' is formed with an arcuate threaded lower surface 22 that is adapted to engage the threaded portion 18 and is further formed with an upstanding threaded post 23 that projects outwardly of the frame 11. Cut away at opposite sides of the cylindrical portion '26 are parallel guide surfaces 24 which seat within sides 25 of a U-shaped bracket 26 that is mounted'on the frame 11 and over the opening 21.

Formed in the bight portion 27 of the bracket 25 is a V-shaped ridge 28 that is formed with a central opening 29 through which the outer end of the post 2 3 extends. the bight portion 27 and against the outer end of the cylindrical portion 20 is a compression spring 30' that is adapted to urge the inner threaded surface 22 of the feed guide 19 into threaded engagement with the threaded portion 18 of the hollow shaft 17. In order to lift the cylindrical portion 20 out of engagement wtih the threaded portion 18, a cam element 31 is provided and is formed witha V-shaped groove 32 that is adapted to cooperate with the V-shaped ridge 28. An opening 33 extends through the cam element 3-1 through which the post 23 extends and a stop nut 34 is mounted on the outer end of the post for engagement by the cam element. When the cam element 31 is snap-turned to align the groove 32 and the ridge 28, the spring 30* urges-the feed guide 19' downwardly so that the threaded lower surface '22. thereof threadably engages the threaded portion 18 of the hollow shaft 17. When the cam element 31 is rotated at right angles with respect to the bracket 26, the groove 32 is lifted out of mating engagement with the ridge 28, thereby causing the cam element 31 to move outwardly. This outward movement of the cam element carries the nut 34 therewith, and since the post 23 is secured to the nut 34, it will also be lifted to retract the threaded surface 22 from en-' gagement with the threaded portion 18.

Referring now to FIGS. 4 and 5, the mouth of the hollow shaft .17 is shown being conically beveled or tapered as indicated at 35, to receive the conically en-' Encircling' the post 23 and bearing against larged split head as of a collet 37. The rear portion of the collet indicated at 38 (FIG. 9) has a longitudinal guide groove 39 formed therein in which a pin 40 seats, the pin 40 being located in an opening formed in the wall of the hollow shaft 17 adjacent the rear end thereof. The rear end of the collet indicated at 41 is threaded and is adapted to receive a draw-in fitting 42 having an internally threaded shell 43 formed thereon which slides in an annular recess 44 in the hollow shaft. The draw-in fitting 42 is adapted to draw in the collet 37 against the tapered mouth of the shaft 17 upon rotation thereof until an armature shaft seated in the collet 37 or in a collet adapter or'diameter adjusting sleeve 45 is tightly gripped. As shown in FIG. 3, a head 46 of the draw-in fitting 42 is formed with a cross slot 47 that is provided with a screw mounting for receiving the turning bar 48' of a handle 49. a

In order to lock the'hollow shaft 1'7 from rotation when the armature shaft is secured in the collet 37, the

rear edge 50 of the frame 11 is formed with a slot 51 for receiving a pin 52 that is mounted on the hollow shaft 17 adjacent the right end thereof as seen in FIG. 1, it being understood that the hollow shaft is free to slide longitudinally with respect to frame 11 when the feed guide 19 is disengaged, whereby pin 52 may be aligned with slot 51 and slid therein. With the hollow. shaft 17 thus locked :from rotation, the draw-in fitting 42 is rotated by the handle 49 thereby causing the collet 37 to move toward the draw-in fitting due to the interengagement of the threaded end 41 and the internally firmly mounted in the collet 1-7, the hollow shaft 17 is slidably moved to the right to move the pin 52 out: of the slot 51.

The apparatus is now ready for the commutator turning operation, and for this purpose a bit or tool 53 is provided that is adjustably mounted in tool holder 54. The tool holder 54 is mounted for axial adjustment in a mounting bracket 55 that is formed with a slot for receiving the holder. threaded openings in the bracket 55- and project into a longitudinally extending groove 57 formed'on the upper surface of the holder 54. Axial adjustment of the holder 54 is effected by loosening 'the bolts 56 and sliding the holder within the bracket 55 as desired. In and out adjustment of the tool 53 is also provided by an adjustment nut 58 that threadably engages a threaded bar 59 and that is secured to the tool 53 by an extension 60 and a set screw 61. Movement of the nut 58 along the length of the bar 59 carries the tool 53 therewith, thereby adjusting the cutting end of the tool with respect to the commutator to be smoothed. A lock nut 62 cooperates with a fixed nut 63 (FIG. 2) to lock the tool '53 from movement therehetween during the commutator cutting operation. a

. In use, the shaft of the armature that carries the commutator to be smoothed is first securely mounted within the collet 37. This is accomplished by locking the hollow Lock bolts 56 extend through shaft 17 from rotation by axially shifting the shaft 17 until the pin 52 on the hollow shaft engages the slot 51 formed in the frame 11. The draw-in fitting 42 is next inserted within the shaft 17 into engagement with the threaded end 41 of the collet 37. The handle 49 is then rotated to draw the collet 37 inwardly into tight gripping relation with the hollow shaft which locks the armature shaftin position. The hollow shaft is next moved axially to the right to free it from the frame 11. The cam element 31 is now rotated so that the the groove 32 coincides with the ridge 28. This drops the cylindrical portion 20 downwardly, and the spring 30 urges the concave threaded surface 22 into threaded engagement with the threaded portion 18. 'After adjustment of the cutter tool; 53, the handle 49 is rotated to rotate the armature commutator and simultaneously feed it axially with respect to the fixed cutter tool 53. Thus it will he'seen that rotation of the same handle 49 is effective to first lock the commutator within the collet and then to rotate and axially feed the commutator for smoothing.

Although I have disclosed a specific constructional feature of my invention, it is obvious that changes in the size, shape, arrangement and positioning of the parts maybe made to meet different armature smoothing requirements, departing from the spirit and the scope of the invention as defined in the appended claims.

What is claimed is:

1. In a device for smoothing the commutator of an armature, a fixed frame having a cylindrical bore, a hollow shaft mounted in said bore for rotatable and axial slidable movement with respect thereto, an externally threaded portion formed on said hollow shaft intermediate the ends thereof, the portions of said bore on opposite sides of said threaded portion defining bearing surfaces for said hollow shaft and the extreme ends of said threaded portion being j located intermediate the bearing ends of said frame re gardless of the axial movement of said hollow shaft with respect to said frame, said hollow shaft having a conically beveled mouth, a collet located in said hollow shaft having an enlarged conical split head and an externally threaded rear portion, means on said collet and shaft cooperating to prevent rotation of said collet while permitting sliding movement of said collet in said hollow shaft, a draw-in fitting poistioned at the rear of said hollow shaft and including an internally threaded shell, means on said hollow shaft and said frame for locking said hollow shaft against rotation when an armature shaft is to be secured in said collet, a handle secured to said draw-in fitting for producing rotation thereof when said hollow shaft is locked against rotation so as to cause the split head of said collet to frictionally lock in the beveled mouth of said hollow shaft and thereby secure the armature shaft within said collet, a feed guide located in said frame and radially movable therein, said feed guide including a threaded surface for engaging said threaded portion, means for urging said threaded surface into engagement with said threaded portion and means for withdrawing said threaded surface out of engagement with said threaded portion, said hollow shaft being movable out of fixed engagement with said frame, wherein said handle is rotated to rotate the draw-in fitting, collet, hollow shaft secured to said collet and armature shaft secured within said collet, the threaded engagement of the feed guide threaded surface with said threaded portion causing said hollow shaft and collet to feed axially upon rotation thereof, and a tool mounted on said frame and fixed with respect to the rotating armature, said tool engag'ng the rotating commutator of said armature for smoothing the surface thereof during the axial movement of said hollow shaft.

2. In a device for smoothing the commutator of an armature, a fixed frame having a cylindrical bore, a hollow shaft mounted in said bore for rotatable and slidable movement with respect thereto, an externally threaded portion formed on said hollow shaft intermediate the ends thereof, the portions of said bore on opposite sides of said threaded portion defining bearing surfaces for said hollow shaft, said threaded portion being located between said bearing surfaces so as not to be externally exposed regardless of the axial movement of said hollow shaft with respect to said frame, a collet extending within said hollow shaft and adapted to be locked in engagement therewith, means on said collet and shaft cooperating to prevent rotation of said collet while permitting sliding movement of said collet in said hollow shaft, a fitting located at the rear of said hollow shaft and threadably engaging the rear end of said collet, means for locking said hollow shaft to said frame when a shaft of said armature is to be secured in said collet, a handle secured to said fitting for producing rotation thereof when said hollow shaft is locked on said frame wherein said collet is locked to said hollow shaft and said armature shaft is locked in said collet, a feed guide fixed against rotation and having a threaded surface for threadably engaging said threaded portion whereupon rotation of said hollow shaft produces a corresponding axial movement thereof, said hollow shaft being movable out of locking engagement with said frame and being rotated by said handle to produce the axial movement thereof, wherein said collet and the armature secured thereto are rotated and axially moved as a unit, and a tool mounted on said frame and fixed with respect to the rotating and axially moving armature for engaging the commutator of said armature and smoothing the surface thereof.

3. In a device for smoothing the commutator of an armature, a fixed frame having a cylindrical bore, a hollow shaft mounted in said bore for rotatable and slidable movement with respect thereto, an externally threaded portion formed on said hollow shaft intermediate the ends thereof, the portions of said bore on opposite sides of said threaded portion defining bearing surfaces for said hollow shaft, a collet extending within said hollow shaft and adapted to be locked in engagement therewith, a fitting located at the rear of said hollow shaft and threadably engaging the rear end of said collet, means for locking said hollow shaft to said frame, a handle secured to said fitting for producing rotation thereof after the hollow shaft has been locked to said frame, wherein said collet is locked to said hollow shaft and said armature shaft is locked in said collet, a feed guide fixed against axial movement and threadably engaging said threaded portion, said hollow shaft being movable out of locking engagement with said frame and being rotated by said handle, whereupon said hollow shaft is axially moved together with said collet and said armature, and a tool mounted on said frame and fixed with respect to the rotating and axially moving armature for engaging the commutator of said armature, thereby smoothing the surface thereof.

4. In a device as set forth in claim 3, said tool being radially and axially adjustable with respect to the peripheral surface of said commutator.

5. In a device as set forth in claim 3, said feed guide including a U-shaped bracket mounted on said frame and positioned over an opening formed therein, said bracket including a V-shaped ridge formed on the bight portion thereof, and a hole extending through said V- shaped ridge, a cylindrical portion having an arcuate bearing surface extending into said opening in said frame and being adapted to engage said threaded portion, a post secured to said cylindrical portion and projecting through said hole in the bight portion of said U-shaped frame, a spring encircling said post and located between said cylindrical portion and the undersur-face of said bight portion for urging said arcuate bearing surface of said cylindrical portion into engagement with said threaded portion, a cam element loosely mounted on said post and including a V-shaped groove for mating with said V-shaped ridge and a stop nut secured to said post and cooperating with said cam element to radially lift said post and cylindrical portion joined thereto wherein said threaded surface is withdrawn from engagement with said threaded portion.

References Cited in the file of this patent UNITED STATES PATENTS 1,841,550 Parker Ian. 19, 1932 2,281,307 John-son Apr. 28, 1942 2,357,765 Rhindress Sept. 5, 1944 2,409,158 Simpson Oct. 8, 1946 2,746,497 Thompson May 22, 1956 

3. IN A DEVICE FOR SMOOTHING THE COMMUTATOR OF AN ARMATURE, A FIXED FRAME HAVING A CYLINDRICAL BORE, A HOLLOW SHAFT MOUNTED IN SAID BORE FOR ROTATABLE AND SLIDABLE MOVEMENT WITH RESPECT THERETO, AN EXTERNALLY THREADED PORTION FORMED ON SAID HOLLOW SHAFT INTERMEDIATE THE ENDS THEREOF, THE PORTIONS OF SAID BORE ON OPPOSITE SIDES OF SAID THREADED PORTION DEFINING BEARING SURFACES FOR SAID HOLLOW SHAFT, A COLLET EXTENDING WITHIN SAID HOLLOW SHAFT AND ADAPTED TO BE LOCKED IN ENGAGEMENT THEREWITH, A FITTING LOCATED AT THE REAR OF SAID HOLLOW SHAFT AND THREADABLY ENGAGING THE REAR END OF SAID COLLET, MEANS FOR LOCKING SAID HOLLOW SHAFT TO SAID FRAME, A HANDLE SECURED TO SAID FITTING FOR PRODUCING ROTATION THEREOF AFTER THE HOLLOW SHAFT HAS BEEN LOCKED TO SAID FRAME, WHEREIN SAID COLLET IS LOCKED TO SAID HOLLOW SHAFT AND SAID ARMATURE SHAFT IS LOCKED 